Life expectancy and prognostic factors for survival in patients with polycythemia vera and essential thrombocythemia

PURPOSE: To assess life expectancy and prognostic factors for survival in patients with polycythemia vera and essential thrombocythemia. METHODS: The study sample consisted of 831 consecutive patients with polycythemia vera (n = 396; 4184 person-years of follow-up) or essential thrombocythemia (n = 435; 4304 person-years of follow-up). Mortality in each group was compared with the Italian population using the standardized mortality ratio (SMR) based on life expectancy data obtained from the Italian Institute of Statistics. RESULTS: The 15-year survival was 65% in patients with polycythemia and 73% in those with thrombocythemia. By Cox regression analysis, the independent predictors of death were a history of thrombosis for polycythemia (hazard ratio [HR] = 2.2; P = 0.0002) and thrombocythemia (HR = 2; P = 0.01), and male sex (HR = 1.8; P = 0.03) for thrombocythemia. Mortality compared with the general population was 1.6-fold higher (P <0.001) in patients with polycythemia but was not increased in those with thrombocythemia (SMR = 1; P = 0.8). CONCLUSION: Life expectancy of patients with polycythemia vera (especially if younger than 50 years) was reduced compared with the general population, whereas life expectancy of patients with essential thrombocythemia was not affected significantly by the disease, reflecting the more indolent nature of the proliferation. History of thrombosis was the main predictor of death in both diseases.